Drugs intended for oral administration in the current market include uncoated tablets, coated tablets, capsules, powders, granules, liquids, and the like. With respect to preparations intended to be disintegrated intraorally and absorbed in an alimentary canal, intraorally disintegrating tablets and fast-dissolving intraoral films have already been marketed.
Such a dosage form is focused on in which a drug is taken by intraorally disintegrating or dissolving the drug only with saliva and without chewing the drug because this dosage form improves benefits of patients and caregivers. This is due to an increase in the number of patients with disability in ingestion of food and drink, in other words, those having difficulty in mastication and swallowing, involving an increase in the old people population. In addition, the Silver Science Kenkyu Houkoku (Silver Science research report) of the former Ministry of Welfare (the present Ministry of Health, Labor and Welfare) named “Koreisha ni toyosaiteki na shinkiseizai oyobi shinkihosoyoki no sakuseikenkyu” (Research of producing an optimal new preparation and packaging container for medicating elderly people), 1988, Masayasu SUGIHARA et al. reported that semisolid formulations (e.g. jelly, yogurt, and pudding) are the expected dosage form of drugs in the future.
The aforementioned backgrounds urge recent development of pharmaceutical jelly preparations, and some kinds of products have been already in the market in Japan.
All of these jelly preparations, however, are of portion-packaged type taken with a spoon or the like tools, or of pillow-packaged type taken by pushing it out from the package. Further, the jelly itself is not intraorally dissolved although it is easily dispersed by physical force upon swallowing.
Examples of water-containing jelly-like preparations disclosed so far include jelly preparations containing carrageenan, locust bean gum, and polyacrylic acid or its partially neutralized product or its salt (see Patent Literature 1); and pharmaceutical jelly compositions containing a jelly base and an alkaline salt (see Patent Literature 2).
These jelly preparations, however, contain a gelling agent thermoreversible at high temperatures (about 60° C. to 100° C.) or contain an irreversible gelling agent which is prepared by cross-linking a gelling agent. In other words, the jelly preparations themselves are not intraorally dissolved but easily dispersed by physical force upon swallowing.
For this reason, these conventional jelly preparations require heating at high temperatures upon preparation or contain a metal salt as a cross-linking agent. Thus, poor stability thereof may be a problem particularly in the case that the preparations contain drugs having poor heat stability or proteins or peptides strongly interacting with metal salts.
In addition, film-shaped preparations are known in which a drug is dispersed or dissolved in a water-soluble polymer, as disclosed in Patent Literatures 3, 4, and the like.
These conventional film-shaped preparations intraorally dissolve or swell by a water-soluble polymer. However, these preparations require a certain amount of saliva for the intraoral dissolution or swell, and therefore patients with dysphagia may require much time for dissolving the preparation.
Further, these film-shaped preparations easily absorb water, so that they easily stick to patient's oral mucosa and cause uncomfortable feeling. Particularly in the case of intraorally dissolvable film-shaped preparations, the solubility, film thickness, and size correlate with each other. As a result, they are difficult to contain a drug in an amount exceeding 100 mg.
Furthermore, with respect to a method of producing such film-shaped preparations, a method is disclosed in which a water-soluble polymer is dissolved in water as a solvent, a drug is dissolved in this aqueous solution, and then the solution is heat-dried to produce a preparation. Particularly in the case of less heat-resistant drugs, however, reduction in an amount of the drug by heat is feared.
In the case of liquid drugs, film-shaped preparations may be dissolved, so that a prescribed shape may not be maintained.